Whitefly-Transmitted Plant Viruses and Their Management

Whiteflies (Hemiptera: Sternorrhyncha: Aleyrodidae) are major agricultural pests that cause economic damage worldwide. These pests commonly referred to a group of tiny, soft-bodied, sap-sucking winged insects generally inhabiting on the underside of the leaf. Moreover, they are enormously polyphagous showing intercrop movement, high reproduction, resistances to insecticides and virus transmission. Since decades, genetic complexity of whiteflies is debatable. Despite the presence of several whitefly species, biotype and genetic species concepts also exist. Like most arthropods, whiteflies too harbour endosymbionts (both primary and secondary), essential for its survival and development. These endosymbionts are specific to species, host and geographic location, which enable easy differentiation among populations of the same species. Apart from causing losses through direct feeding, they also act as vector for various economically important plant viruses like Begomovirus, Geminivirus, etc., and transmit viral particles via persistent and semi-persistent mode of transmission. Management of whitefly populations, and, in particular, management of the viral plant diseases it transmits, is difficult. At present, the use of insecticides is the main approach employed to manage whiteflies. However, due to both environmental concern and resistance issue, this practice is greatly restricted. Hence, integrated pest management programme with all available tactics would help in reducing the pest population.